A connection box for a solar panel typically has a base that is mounted directly on the panel and has a floor and a wall defining with a removable cover a compartment. A panel-output conductor or line enters the compartment normally through a hole in the floor and a feed cable that goes to the user or network getting the electricity generated by the solar panel passes out through a hole in the wall of the base, where a strain relief is typically provided for this fable.
A connection box of this type is known from DE 8,422, 774, in which the feed cable is set in a groove in the floor of the box and clamped down by a screw-on strap to relieve strain.
It is known on the one hand to provide the side wall of the base, which delimits the compartment, with threaded sleeves having crimp tongues. After the feed cable is routed through the threaded sleeve and the wall cutout into the compartment, a cap nut is screwed onto the threaded sleeve to press the crimp tongues against the insulation sheath of the feed cable and thus holds to relieve on the connection box and cable.
Inserting cables for strain relief in a nonstraight channel is also known, which is not possible with the feed cables for solar panels because of their rigidity, however.
The above-described prior art has two disadvantages. On the one hand, separate work steps that are difficult to automate are necessary for the strain-relieving fixing of the feed cable, on the other hand, the strain-relief arrangements are separate components. In view of the rising cost pressure in the manufacturing of the connection boxes of this type, improvements in this regard are to be developed.
Another known solution is a contact crimped on the end of the feed cable and having a part of the strain-relief assembly. The contact is fastened using an insulation crimp ring on the feed cable. The section of the feed cable provided with the insulation crimp ring is inserted in a holding seat formed in the base of the connection box, to relieve strain. This strain-relief arrangement is generally satisfactory but does not meet an American testing norm for strain relief testing, for example. Specifically, thins text requires that the contact for connection to the connection box of the panel-output conductor cannot be a component of the strain-relief arrangement. As a result, according to the testing specification, the feed cable is cut the contact and the strain-relief testing is then performed. Since the insulation crimp ring is a component of the contact, this procedure greatly weakens the assembly and ensures failure of the test.